6.14 Using the grammar of Figure 6.17, draw parse trees and abstract syntax trees for the arithmetic expressions: (a) ((2)) (b) 3+4+5+6*7 (c) 3+4+5+6+7 (d) 3* (4+5)*(6+7) (e) (2+(3+(4+5))) figure 6.17 expr expr + term | term term term + factor | factor factor (expr) | number number number digit | digit digit0|1|2|3|4|5| 6 | 7 | 8 | 9